In the field of business forms, the bifolded mailer is a popular item. In general, a bifolded mailer at its simplest comprises a sheet with two longitudinally spaced, parallel transverse folds in the same direction dividing the sheet into a head panel, a middle panel and a foot panel. With the sheet folded on the fold lines, the mailer is fastened closed, thereby enclosing a communication printed or otherwise applied on one face of the sheet. If the item is to be delivered by mail, the other face of one of the panels may be provided with the name and postal address of the intended recipient, statement of postal class, franking information, a return address, a stamp and/or the like.
On more elaborate conventional bifold mailers, the folded sheet is held closed by a pattern of adhesive applied to various perimetrical margins of the panels, which serve to maintain the confidentiality of the communication included on the obscured surfaces of the document until the mailer is opened up. Opening is facilitated by placement of perforation lines which e.g. allow one or more marginal strips to be torn off in order to gain visual access to the surfaces that were obscured.
It is considered to be a valuable feature of business forms, that all variable information can be applied on one face, especially in one pass, on the form stock, regardless of whether the pre-applied relatively non-varying printing is provided on one or both faces of the form stock, and regardless of whether the form stock is provided by the form manufacturer to the business user as a web of indeterminate length or as a stack of cut sheets.
A very convenient conventional way of accomplishing this objective, is to provide one panel of the mailer stock with a window aperture which, in the course of folding and sealing the mailer, comes to expose the intended recipient's name and postal address as variably printed on the opposite face of another panel of the mailer stock.
Often, the business user of such form stock would like to include as an enclosure of a bifolded mailer, a sheet, check, booklet, card, return envelope or the like, having a size that is at least slightly shorter and narrower than the internal size of the bifolded mailer.
The conventional windowed, perforated, adhered margin, bifolded mailer presents two problems to anyone who would wish to enclose such an enclosure sheet or the like within the mailer. First, unless the enclosure is relatively small or odd-shaped and held against lateral movement within the enclosed space, it is almost certain to obscure the name and postal address of the intended recipient, making the mailer difficult or impossible to deliver. Second, unless the enclosure is relatively small and held so as to have a particular juxtaposition relative to the perforated marginal tear strip or tear strips that the recipient will tear-off for gaining access to the communication within the mailer, the user is very likely to also tear off a marginal part of the enclosure.
Further, conventional bifolded mailers are often difficult to reliably stuff with enclosures using available automated machinery.